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Monthly Archives: May 2014

It’s too easy for me to get caught up in the magic and mystery of geodesic domes – what are the empirical components that make domes more than just “way-cool groovy structures, man” and actually a solid technology for supporting human endeavors and improving the social and material quality of human agency?

These pictures are taken from the Dome Council of America’s White Paper on Dome Home Energy Efficiency from 1986. Sadly I can’t find the NDC as an extant organization any more…

This first picture shows the wind pressure resistance that each type of structure exhibits – you can see that the rectilinear structure presents a flat surface to the wind “this combined action results in more infiltration of external air and in a greater exfiltration of internal air”* – basically cold air gets in and hot air is sucked out. Much less so with a geodesic/spherical structure:

This next picture illustrates the flow of warm air in a dome – warm air rises and then circulates back to the floor, creating a more even temperature throughout the structure. Not so with a rectilinear structure…:

Essentially, what the NDC was trying to demonstrate was that the dome home costs less to insulate to achieve energy efficiency – either allowing the homeowner to either uses insulation with a lower R-value, or by using a regular or higher R-value insulation use less energy to heat the structure – both methods resulting in a reduction of energy costs.

This last picture illustrates the disparity in surface area to living space in a geodesic dome home compared to rectilinear structures:

This very simply demonstrates that geodesic structures require less material to construct for the same amount of livable area/floorspace. Which again results in a reduction of construction costs which means a lower carbon footprint.

So say you actually wanted to build a wooden dome for habitation, and not just a chicken coop or plastic wrapped greenhouse – what are the materials you would need? Having worked as a carpenter building houses, I have fortunately participated in building from the ground up – from marking out a site/creating profiles, excavation of foundations, laying a floor, building/construction walls doors stairs, cladding all the way to lock up and finishing. All while working in amongst the associated plumbing and electrical trades.

In terms of a wooden geodesic dome using the strut and hub method (see pictures here for the “doghead” strut/hub attachment method as pioneered and designed by Patrick Martin, though the upper hubs utilized a much more cut-out-shape-fitting round metal plate instead of the very minimum requirement square metal plate seen here):

your almost exhaustive shopping list looks something like this (note that lengths and amounts are not included as this is a universal list that will be individuated by exact specificity):

* antcapping

* hoop iron for riser walls

* nails, screws and other fixings

* dampcourse/alligator skin

* flashing

* plywood and/or corrugated iron

* gyprock/plaster/architraves

* bolts/nuts/washers

* thick wire

* timber (90×45 mm)

* insulation bats

* blue paper (insulating paper)

* windows/doors

* hinges for doors and opening panels/windows

* metal disc plates for hubs

* 1 x concrete slab 😉

* chemset bolts/dyna bolts/concrete nails

Beyond this are the materials required by the plumbers and electricians. It should be noted that the strut and hub method in wood provides an excellent cavity for electrical conduit and insulation bats, as you can see in this picture where the interior walls were never attached (plus you get to see a picture of the second story and the beautiful light pouring in from the raised flat roof/floor the cupola sits on):

though I do have an appreciation for external utility access (rather than internal, inside the wall cavity), I’m sure that unless such external conduits were very well integrated into the décor they would leave a lot to be desired in terms of aesthetics and interior design…

Plumbing likewise can, depending on the thickness of the struts, be accommodated by this cavity.

During the pitch Joana and Sandi asked plenty of pertinent questions, and Joana’s architectural eye flipped the dome on its side to demonstrate the spherical possibilities and the modular nature of the structure. It was clear to all that I had a lot of passion and experience with the theoretical and practical applications of the technology, but also evident that perhaps there was too broad a focus for what I was actually pitching. Sandi, ever the sensible head when it comes to my more expansive flights of fancy wanted to know exactly what materials would be involved in the “chassis” (struts? If so, what material? panels? If so, again, what materials) and what the exact function and purpose this pitch had for the dome.

I would have to admit even to myself that this is always something I have struggled with – in essence the domes are a possibility until there is a reason to create them. I have built domes out of wood salvaged from transport pallets, cardboard, finished pine, steel, reclaimed Hills Hoists, small iron bars, tent poles, plastic conduit bamboo; and clad them in plastic sheeting, tarps, corrugated iron, “for sale” signs, laserlite, canvas, canvas dipped in cement, wooden wallboards – sometimes for a distinct reason, other times as part of research and development.

Here again is a picture of the wooden frame dome Patrick and I built, covered in plywood and sitting on a 900mm riser. This dome has a second story inside with stairs and a wooden floor, and a small cupola on top reached via a ladder. Kept warm by a wood fire I lived in it (on the second floor) for about 6 months during the winter of 2009. It ain’t pretty, but it was definitely a proof of concept…

Where will the raw material be sourced from? Once sourced, how will the “product” be manufactured and by whom? Once manufactured, how will it be transported? Once transported, who will assemble it? Once assembled, who will clad it? Once finished, what maintenance and after supply service will be required? Are all of these questions auto-assumptions, or are some of them unnecessary – if the purpose is disaster shelter, then perhaps the raw materials can be sourced in the disaster zone, and the assembly could be completed by the survivors? If the purpose is a sustainability-minded chook-shelter, is the “product” merely the instructions and a YouTube video on how to manufacture the struts and assemble the dome from cast off recycled timber or discarded Hill’s Hoists and some tire wire?